C# to VB.NET

I have put this code through various translators:
using System;
using System.Web.Security;
using System.Web.UI;

public partial class _Default : Page, ICallbackEventHandler
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string cbReference = Page.ClientScript.GetCallbackEventReference(this, "arg", "displayResult", "", true);

        string CallbackScript = "function CallServer(arg, context){" + cbReference + "; }";

        Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "CallBack", CallbackScript, true);
    }

    protected string IsUserExist;

    public void RaiseCallbackEvent(string eventArgument)
  &n ...